Advice?

One of my goals this year is to implement Love and Logic strategies to help manage student behaviors and create more space for teaching and learning.  On that note, I'm looking for some ideas :o)

I am finding out that my two different classes have two very different personalities.  My morning class, for the most part, is quick to follow directions, excited to learn, and able to make changes with reminders.  In my afternoon class, I have about five students who are quite defiant and often choose to do the opposite of what they have been asked to do.  This, of course, changes the entire feel of the classroom and the amount of work we're able to complete within our time.  I've figured out that how the day goes kind of hinges on the behavior of one particular student.  The others fall in line.  I would love to hear ideas I could try to make the school day a more positive experience for him as well as for the rest of the kids in class.

So far, I have had some success removing privileges and having him practice appropriate behaviors during those times.  That does not seem to have a lasting effect from one day to the next, however.  He struggles with taking a break in the classroom because he continues to draw attention to himself there, and he now refuses to leave the classroom to take a break somewhere else. 

I know I need to continue to work on building a positive relationship with him for lasting change to take place, but I could use some help in the short term.